rebase and address comments

Author: huaxingao

spark/src/main/scala/org/apache/comet/rules/CometScanRule.scala

@@ -30,7 +30,6 @@ import org.apache.spark.sql.execution.{FileSourceScanExec, SparkPlan}
 import org.apache.spark.sql.execution.datasources.HadoopFsRelation
 import org.apache.spark.sql.execution.datasources.v2.BatchScanExec
 import org.apache.spark.sql.execution.datasources.v2.parquet.ParquetScan
-import org.apache.spark.sql.internal.SQLConf
 
 import org.apache.comet.CometConf
 import org.apache.comet.CometConf._